1986 XR100R not working good

hi i just got this 1986 XR100R (first time starting it since I got it) and when the head and case is at room temp. it will start up 2 kicks but once u get it up to operating temp. and start going in 1st gear and once you get it to half throttle it bogs like carzy and it does that in every gear. i think it might be a vacume leek but i'm not sure. what could it be??

Thanx,
john